Low resistance exhaust sytem for the MGB ?

DaviesDJ · Post by **DaviesDJ** » Sun Dec 29, 2013 4:44 pm

Hi perry mate, looking awesome!! Would a tapered cut at the end of each primary reduce resistance even more? The CSA would be greatly increased by this and we use this in work to increase flow in smaller cannulas when only a tiny one can be inserted?? I also like the look of this?
Cheers

Dave

mgbv8 · Post by **mgbv8** » Sun Dec 29, 2013 10:59 pm

Hmm!!
The bosses on 7 and 8 are probably 12" away from the ports. But on 1 and 2 the bosses are about 9" from the ports.

I wanted to keep the sensors below the bonnet, and as the bonnet slopes down towards the front... You get the idea eh?

When I do my first full power runs I'll keep the lambda in the rear pair and fit the EGT's in the front pair. I'll bung Mikes GoPro in the car to record EGT's to see how high they are.

I'm not sure how long the pipes will end up though. I'll have to see how they colour up with use first. I'm not sure about slash cutting the pipe ends?

mgbv8 · Post by **mgbv8** » Tue Dec 31, 2013 7:32 pm

Final test today with the header flanges now port matched.

I'm seeing some spiking on the drivers side afr but thats because the plug leads on that side run close to the sensor. I'll put the sensors in the rear pair and stick EGT in the front pair while doing first test runs so I can see how hot the lambda would get when racing.

Sounds a lot deeper now at idle, but the cam does not really pick the sound up that well. Still make my ears ring as well

http://www.youtube.com/watch?v=ukV9ltEhyTA&feature=c4-overview&list=UUqIlXfSAoiZ--GyG4tfRrjw

DaviesDJ · Post by **DaviesDJ** » Tue Dec 31, 2013 8:46 pm

What AFR are you aiming for at WOT Pel?

mgbv8 · Post by **mgbv8** » Tue Dec 31, 2013 8:51 pm

DaviesDJ wrote:What AFR are you aiming for at WOT Pel?

On boost and nitrous I'll be aiming for 12

DaviesDJ · Post by **DaviesDJ** » Tue Dec 31, 2013 10:05 pm

Ahhh, I was going to aim for high 11s for NOS, but I have weaker pistons. Are you using progressive fees or fixed hit??

mgbv8 · Post by **mgbv8** » Tue Dec 31, 2013 10:18 pm

DaviesDJ wrote:Ahhh, I was going to aim for high 11s for NOS, but I have weaker pistons. Are you using progressive fees or fixed hit??

I have been running mid 10's but that costing me some power I think. So I'm going to lean it out just a little to go high 11's to low 12's if all goes well.

I'm using a basic progressive controller which can start at about 10% of full nitrous power and ramp it up to 100% over 10 seconds. It also has the option to run a reset option so the power build can either go back to the start for a gear change, or stay where it was in the power build while you change gears and then carry on from there. I dont lift off the pedal for my gear shift so the reset is off and it does just one power build. And as the engine has got stronger and stronger I've tweaked the ramp time and power down to a 100 shot off the line with the other 75hp coming in over 0.8 of a second after I hit full throttle. You can see this happening in the slo mo vids. Although I think the engine would take the whole 175 shot as a fixed hit off the line.

On the old engine before the blower I used to hit it with 150 off the line and bring in the other 150 in over 1.5 seconds.

The Omega pistons have really done well.

Post by **scudderfish** » Wed Jan 01, 2014 10:10 am

So where's the vid of starting it with the tennis balls on then?

I'm sure if you numbered them and measured how far they went you could use it as some sort of diagnostic....

kiwicar · Post by **kiwicar** » Wed Jan 01, 2014 10:51 am

Hi
It would be one way of checking the firing order

best regards
Mike

DaviesDJ · Post by **DaviesDJ** » Wed Jan 01, 2014 2:33 pm

Just opened land rover monthly! They are giving away 4 picture cards, and one of them is my car!